Ethnic Differences In Post-prandial Glycemic Control After Acute Moderate-intensity Continuous Or High-intensity Interval Exercise

Abstract

PURPOSE: To examine the effects of acute continuous moderate-intensity aerobic exercise (CME) and low-volume high-intensity interval training (LV-HIIT) on glycemic control in white Europeans (WEs) and south Asians (SAs) with impaired glycemic control. METHODS: 23 participants (WE / SA [M/F]: 13[6/7] / 10[7/3]; median (IQR): age 67 (60–68) years, BMI 30.0 (28.4–32.8) kg/m2, waist circumference 100.8 (97.6–109.1) cm, HbA1c 5.9 (5.8–6.1) %) completed three 6 h trials (control [CON], CME, LV-HIIT; randomized order). Participants rested throughout, except for 35 min of CME and 25 min of LV-HIIT (closely matched for external work produced) during corresponding trials. Both CME and LV-HIIT ended at 2 h. Standardized meals were consumed at 0 and 3 h. Plasma glucose and insulin were measured at 0, 0.5, 1, 2, 3, 3.5, 4, 5 and 6 h. Data were analysed as post-exercise time-averaged area under the curve (AUCpost), using generalized estimating equations, adjusted for pre-exercise AUC (also time-averaged), sex and age. Main effects of trial and ethnicity were assessed, with an interaction term fitted to explore if ethnicity modulated responses. Insulin resistance index (IRI) was calculated as tAUCglu x tAUCins. RESULTS: Glucose was unaffected (all p ≥ 0.28), but insulin AUCpost was reduced in both exercise trials compared to CON (main effect p < 0.001; Figure 1A). Furthermore, this effect was modulated by ethnicity (p = 0.03), with a greater effect seen in SAs. Notably, insulin AUCpost was similar in both ethnicities during exercise trials, despite being higher in SAs during CON (Figure 1A). Results were similar for IRI (Figure 1B). CONCLUSION: Despite ~30% higher post-prandial insulin responses during prolonged sitting, SAs may benefit more from acute exercise than WEs. Acknowledging that this was an acute-crossover study, these findings warrant further investigation with longer-term exercise training interventions, given the higher cardiometabolic disease risk observed in SAs.